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BUG: KMSAN: kernel-infoleak in copyout+0x16b/0x1f0 lib/iov_iter.c:145
CPU: 1 PID: 13250 Comm: blkid Not tainted 5.2.0-rc4+ #4
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x162/0x2d0 mm/kmsan/kmsan.c:611
 kmsan_internal_check_memory+0x974/0xa80 mm/kmsan/kmsan.c:705
 kmsan_copy_to_user+0xa9/0xb0 mm/kmsan/kmsan_hooks.c:495
 copyout+0x16b/0x1f0 lib/iov_iter.c:145
 copy_page_to_iter_iovec lib/iov_iter.c:217 [inline]
 copy_page_to_iter+0x6dc/0x1910 lib/iov_iter.c:906
 generic_file_buffered_read mm/filemap.c:2118 [inline]
 generic_file_read_iter+0x2979/0x3e70 mm/filemap.c:2298
 blkdev_read_iter+0x20d/0x270 fs/block_dev.c:1983
 call_read_iter include/linux/fs.h:1866 [inline]
 new_sync_read fs/read_write.c:414 [inline]
 __vfs_read+0xa67/0xc90 fs/read_write.c:427
 vfs_read+0x359/0x6f0 fs/read_write.c:461
 ksys_read+0x265/0x430 fs/read_write.c:587
 __do_sys_read fs/read_write.c:597 [inline]
 __se_sys_read+0x92/0xb0 fs/read_write.c:595
 __x64_sys_read+0x4a/0x70 fs/read_write.c:595
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x7f19dc912310
Code: 73 01 c3 48 8b 0d 28 4b 2b 00 31 d2 48 29 c2 64 89 11 48 83 c8 ff eb ea 90 90 83 3d e5 a2 2b 00 00 75 10 b8 00 00 00 00 0f 05 <48> 3d 01 f0 ff ff 73 31 c3 48 83 ec 08 e8 6e 8a 01 00 48 89 04 24
RSP: 002b:00007ffe93afb2c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f19dc912310
RDX: 0000000000000100 RSI: 00000000006f5df8 RDI: 0000000000000003
RBP: 00000000006f5dd0 R08: 0000000000000028 R09: 0000000001680000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000006f5030
R13: 0000000000000100 R14: 00000000006f5080 R15: 00000000006f5de8

Uninit was created at:
 kmsan_save_stack_with_flags+0x37/0x70 mm/kmsan/kmsan.c:201
 kmsan_internal_alloc_meta_for_pages+0x123/0x510 mm/kmsan/kmsan_hooks.c:102
 kmsan_alloc_page+0x7a/0xf0 mm/kmsan/kmsan_hooks.c:246
 __alloc_pages_nodemask+0x144d/0x6020 mm/page_alloc.c:4700
 alloc_pages_current+0x6a0/0x9b0 mm/mempolicy.c:2132
 alloc_pages include/linux/gfp.h:511 [inline]
 __page_cache_alloc+0x95/0x320 mm/filemap.c:955
 pagecache_get_page+0x443/0x11f0 mm/filemap.c:1645
 grab_cache_page_write_begin+0x100/0x180 mm/filemap.c:3159
 block_write_begin+0xdd/0x340 fs/buffer.c:2078
 blkdev_write_begin+0xf5/0x110 fs/block_dev.c:639
 generic_perform_write+0x424/0x990 mm/filemap.c:3209
 __generic_file_write_iter+0x421/0xa30 mm/filemap.c:3338
 blkdev_write_iter+0x3ef/0x650 fs/block_dev.c:1963
 call_write_iter include/linux/fs.h:1872 [inline]
 new_sync_write fs/read_write.c:483 [inline]
 __vfs_write+0xa2c/0xcb0 fs/read_write.c:496
 vfs_write+0x481/0x920 fs/read_write.c:558
 ksys_write+0x265/0x430 fs/read_write.c:611
 __do_sys_write fs/read_write.c:623 [inline]
 __se_sys_write+0x92/0xb0 fs/read_write.c:620
 __x64_sys_write+0x4a/0x70 fs/read_write.c:620
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Bytes 68-255 of 256 are uninitialized
Memory access of size 256 starts at ffff8880b8371000
Data copied to user address 00000000006f5df8
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